Color balanced ophthalmic system with selective light inhibition

ABSTRACT

An ophthalmic system is provided. The system includes an ophthalmic material doped with a dye that absorbs light in a wavelength range and a layer that corrects a color imbalance caused by absorption of light by the dye. The dye can absorb light in a harmful spectral region, such as a narrow blue region. The color balancing layer may allow a user to have a color neutral view when using the system.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.11/378,317 filed Mar. 20, 2006, and claims the benefit of U.S.Provisional Application No. 60/812,628 filed Jun. 12, 2006, each ofwhich is incorporated herein by reference in its entirety.

BACKGROUND

Current research strongly supports the premise that short wavelengthvisible light (blue light) having a wavelength of approximately 400nm-500 nm (nanometers or 10⁻⁹ meters) could be a contributing cause ofAMD (age related macular degeneration). It is believed that the highestlevel of blue light absorption occurs in a region around 430 nm, such as400 nm-460 nm. Research further suggests that blue light worsens othercausative factors in AMD, such as heredity, tobacco smoke, and excessivealcohol consumption.

Light is made up of electromagnetic radiation that travels in waves. Theelectromagnetic spectrum includes radio waves, millimeter waves,microwaves, infrared, visible light, ultra-violet (UVA and UVB) andx-rays and gamma rays. The human retina responds only to the visiblelight portion of the electromagnetic spectrum. The visible lightspectrum includes the longest visible light wavelength of approximately700 nm and the shortest of approximately 400 nm. Blue light wavelengthsfall in the approximate range of 400 nm to 500 nm. For the ultra-violetbands, UVB wavelengths are from 290 nm to 320 nm and UVA wavelengths arefrom 320 nm to 400 nm.

The human retina includes multiple layers. These layers listed in orderfrom the first exposed to any light entering the eye to the deepestinclude:

1) Nerve Fiber Layer

2) Ganglion Cells

3) Inner Plexiform Layer

4) Bipolar and Horizontal Cells

5) Outer Plexiform Layer

6) Photoreceptors (Rods and Cones)

7) Retinal Pigment Epithelium (RPE)

8) Bruch's Membrane

9) Choroid

When light is absorbed by the eye's photoreceptor cells, (rods andcones) the cells bleach and become unreceptive until they recover. Thisrecovery process is a metabolic process and is called the “visualcycle.” Absorption of blue light has been shown to reverse this processprematurely. This premature reversal increases the risk of oxidativedamage and is believed to lead to the buildup of the pigment lipofuscinin the retina. This build up occurs in the retinal pigment epithelium(RPE) layer. It is believed that aggregates of extra-cellular materialscalled drusen are formed in the RPE layer due to the excessive amountsof lipofuscin. Drusen hinder or block the RPE layer from providing theproper nutrients to the photoreceptors, which leads to damage or evendeath of these cells. To further complicate this process it appears thatwhen lipofuscin absorbs blue light in high quantities it becomes toxic,causing further damage and/or death of the RPE cells. It is believedthat the lipofuscin constituent A2E is at least partly responsible forthe short-wavelength sensitivity of RPE cells. A2E has been shown to bemaximally excited by blue light; the photochemical events resulting fromsuch excitation can lead to cell death. See, for example, Janet R.Sparrow et al., “Blue light-absorbing intraocular lens and retinalpigment epithelium protection in vitro,” J. Cataract Refract. Surg.2004, vol. 30, pp. 873-78.

The lighting and vision care industries have standards as to humanvision exposure to UVA and UVB radiation Surprisingly, no such standardis in place with regard to blue light. For example, in the commonfluorescent tubes available today, the glass envelope mostly blocksultra-violet light but blue light is transmitted with littleattenuation. In some cases, the envelope is designed to have enhancedtransmission in the blue region of the spectrum.

Ophthalmic systems that provide blue blocking to some degree are known.However, there are disadvantages associated with such systems. Forexample, they tend to be cosmetically unappealing because of a yellow oramber tint that is produced in lenses by blue blocking. Morespecifically, one common technique for blue blocking involves tinting ordyeing lenses with a blue blocking tint, such as BPI Filter Vision 450or BPI Diamond Dye 500. The tinting may be accomplished, for example, byimmersing the lens in a heated tint pot containing a blue blocking dyesolution for some predetermined period of time. Typically, the dyesolution has a yellow or amber color and thus imparts a yellow or ambertint to the lens. To many people, the appearance of this yellow or ambertint may be undesirable cosmetically. Moreover, the tint may interferewith the normal color perception of a lens user, making it difficult,for example, to correctly perceive the color of a traffic light or sign.

Efforts have been made to compensate for the yellowing effect ofconventional blue blocking filters. For example, blue blocking lenseshave been treated with additional dyes, such as blue, red or green dyes,to offset the yellowing effect. The treatment causes the additional dyesto become intermixed with the original blue blocking dyes. However,while this technique may reduce yellow in a blue blocked lens,intermixing of the dyes may reduce the effectiveness of the blueblocking by allowing more of the blue light spectrum through. Moreover,these conventional techniques undesirably reduce the overalltransmission of light wavelengths other than blue light wavelengths.This unwanted reduction may in turn result in reduced visual acuity fora lens user.

In view of the foregoing, there is a need for an ophthalmic system thatallows for selective blockage of wavelengths of blue light while at thesame time transmitting in excess of 80% of visible light and beingperceived as mostly color neutral by someone observing the ophthalmicsystem when worn by a wearer. In addition, it is further important thatsuch a system not impair the wearer's color vision and further thatreflections from the back surface of the system into the eye of thewearer be at a level of not being objectionable to the wearer. This needexists as more and more data is pointing to blue light as one of thepossible contributory factors in macula degeneration (the leading causeof blindness in the industrialized world) and also other retinaldiseases.

SUMMARY OF THE INVENTION

The present invention relates to an ophthalmic system. Moreparticularly, the invention relates to an ophthalmic system thatperforms blocking of blue light wavelengths, while presenting acosmetically attractive product.

An ophthalmic system is provided that can provide 80% or bettertransmission of visible light, inhibit selective wavelengths of bluelight, allow for the wearer's proper color vision performance, andprovide a mostly color neutral appearance to an observer looking at thewearer wearing such a lens or lens system. The system may use variousoptical coatings, films, materials, and absorbing dyes to produce thedesired effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show examples of an ophthalmic system including aposterior blue blocking component and an anterior color balancingcomponent.

FIG. 2 shows an example of using a dye resist to form an ophthalmicsystem.

FIG. 3 illustrates an exemplary system with a blue blocking componentand a color balancing component integrated into a clear or mostly clearophthalmic lens.

FIG. 4 illustrates an exemplary ophthalmic system formed using anin-mold coating.

FIG. 5 illustrates the bonding of two ophthalmic components.

FIG. 6 illustrates exemplary ophthalmic systems using anti-reflectivecoatings.

FIGS. 7A-7C illustrate various exemplary combinations of a blue blockingcomponent, a color balancing component, and an ophthalmic component.

FIGS. 8A and 8B show examples of an ophthalmic system including amulti-functional blue blocking and color-balancing component.

FIG. 9 shows a reference of observed colors that correspond to variousCIE coordinates.

FIG. 10 shows the transmission of the Gentext E465 absorbing dye.

FIG. 11 shows the absorbance of the Gentex E465 absorbing dye.

FIG. 12 shows the transmittance of a polycarbonate substrate with a dyeconcentration suitable for absorbing in the 430 nm range.

FIG. 13 shows the transmittance as a function of wavelength of apolycarbonate substrate with an antireflective coating.

FIG. 14 shows the color plot of a polycarbonate substrate with anantireflective coating.

FIG. 15 shows the transmittance as a function of wavelength of anuncoated polycarbonate substrate and a polycarbonate substrate with anantireflective coating on both surfaces.

FIG. 16 shows the spectral transmittance of a 106 nm layer of TiO₂ on apolycarbonate substrate.

FIG. 17 shows the color plot of a 106 nm layer of TiO₂ on apolycarbonate substrate.

FIG. 18 shows the spectral transmittance of a 134 nm layer of TiO₂ on apolycarbonate substrate.

FIG. 19 shows the color plot of a 134 nm layer of TiO₂ on apolycarbonate substrate.

FIG. 20 shows the spectral transmittance of a modified AR coatingsuitable for color balancing a substrate having a blue absorbing dye.

FIG. 21 shows the color plot of a modified AR coating suitable for colorbalancing a substrate having a blue absorbing dye.

FIG. 22 shows the spectral transmittance of a substrate having a blueabsorbing dye.

FIG. 21 shows the color plot of a substrate having a blue absorbing dye.

FIG. 23 shows the spectral transmittance of a substrate having a blueabsorbing dye and a rear AR coating.

FIG. 24 shows the color plot of a substrate having a blue absorbing dyeand a rear AR coating.

FIG. 25 shows the spectral transmittance of a substrate having a blueabsorbing dye and AR coatings on the front and rear surfaces.

FIG. 26 shows the color plot of a substrate having a blue absorbing dyeand AR coatings on the front and rear surfaces.

FIG. 25 shows the spectral transmittance of a substrate having a blueabsorbing dye and a color balancing AR coating.

FIG. 26 shows the color plot of a substrate having a blue absorbing dyeand a color balancing AR coating.

DETAILED DESCRIPTION

Embodiments of the present invention relate to an ophthalmic system thatperforms effective blue blocking while at the same time providing acosmetically attractive product, normal or acceptable color perceptionfor a user, and a high level of transmitted light for good visualacuity. An ophthalmic system is provided that can provide an averagetransmission of 80% or better transmission of visible light, inhibitselective wavelengths of blue light (“blue blocking”), allow for thewearer's proper color vision performance, and provide a mostly colorneutral appearance to an observer looking at the wearer wearing such alens or lens system. As used herein, the “average transmission” of asystem refers to the average transmission at wavelengths in a range,such as the visible spectrum. A system also may be characterized by the“luminous transmission” of the system, which refers to an average in awavelength range, that is weighted according to the sensitivity of theeye at each wavelength. Systems described herein may use various opticalcoatings, films, materials, and absorbing dyes to produce the desiredeffect.

More specifically, embodiments of the invention may provide effectiveblue blocking in combination with color balancing. “Color balancing” or“color balanced” as used herein means that the yellow or amber color, orother unwanted effect of blue blocking is reduced, offset, neutralizedor otherwise compensated for so as to produce a cosmetically acceptableresult, without at the same time reducing the effectiveness of the blueblocking. For example, wavelengths at or near 400 nm-460 nm may beblocked or reduced in intensity. In particular, for example, wavelengthsat or near 420-440 nm may be blocked or reduced in intensity.Furthermore, transmission of unblocked wavelengths may remain at a highlevel, for example at least 80%. Additionally, to an external viewer,the ophthalmic system may look clear or mostly clear. For a system user,color perception may be normal or acceptable.

An “ophthalmic system” as used here includes prescription ornon-prescription ophthalmic lenses used, e.g., for glasses (orspectacles), sunglasses, contact lenses, intra-ocular lenses, cornealinlays, corneal on-lays, and may be treated or processed or combinedwith other components to provide desired functionalities described infurther detail herein. As used herein, an “ophthalmic material” is onecommonly used to fabricate an ophthalmic system, such as a correctivelens. Exemplary ophthalmic materials include glass, plastics such asCR-39, Trivex, and polycarbonate materials, though other materials maybe used and are known for various ophthalmic systems.

An ophthalmic system may include a blue blocking component posterior toa color-balancing component. Either of the blue blocking component orthe color balancing component may be, or form part of, an ophthalmiccomponent such as a lens. The posterior blue blocking component andanterior color balancing component may be distinct layers on or adjacentto or near a surface or surfaces of an ophthalmic lens. Thecolor-balancing component may reduce or neutralize a yellow or ambertint of the posterior blue blocking component, to produce a cosmeticallyacceptable appearance. For example, to an external viewer, theophthalmic system may look clear or mostly clear. For a system user,color perception may be normal or acceptable. Further, because the blueblocking and color balancing tints are not intermixed, wavelengths inthe blue light spectrum may be blocked or reduced in intensity and thetransmitted intensity of incident light in the ophthalmic system may beat least 85% for unblocked wavelengths.

As discussed previously, techniques for blue blocking are known. Theknown techniques to block blue light wavelengths include absorption,reflection, interference, or any combination thereof. As discussedearlier, according to one technique, a lens may be tinted/dyed with ablue blocking tint, such as BPI Filter Vision 450 or BPI Diamond Dye500, in a suitable proportion or concentration. The tinting may beaccomplished, for example, by immersing the lens in a heated tint potcontaining a blue blocking dye solution for some predetermined period oftime. According to another technique, a filter is used for blueblocking. The filter could include, for example, organic or inorganiccompounds exhibiting absorption and/or reflection of and/or interferencewith blue light wavelengths. The filter could comprise multiple thinlayers or coatings of organic and/or inorganic substances. Each layermay have properties, which, either individually or in combination withother layers, absorbs, reflects or interferes with light having bluelight wavelengths. Rugate notch filters are one example of blue blockingfilters. Rugate filters are single thin films of inorganic dielectricsin which the refractive index oscillates continuously between high andlow values. Fabricated by the co-deposition of two materials ofdifferent refractive index (e.g. SiO₂ and TiO₂), rugate filters areknown to have very well defined stop-bands for wavelength blocking, withvery little attenuation outside the band. The construction parameters ofthe filter (oscillation period, refractive index modulation, number ofrefractive index oscillations) determine the performance parameters ofthe filter (center of the stop-band, width of the stop band,transmission within the band). Rugate filters are disclosed in moredetail in, for example, U.S. Pat. Nos. 6,984,038 and 7,066,596, each ofwhich is by reference in its entirety. Another technique for blueblocking is the use of multi-layer dielectric stacks. Multi-layerdielectric stacks are fabricated by depositing discrete layers ofalternating high and low refractive index materials. Similarly to rugatefilters, design parameters such as individual layer thickness,individual layer refractive index, and number of layer repetitionsdetermine the performance parameters for multi-layer dielectric stacks.

Color balancing may comprise imparting, for example, a suitableproportion or concentration of blue tinting/dye, or a suitablecombination of red and green tinting/dyes to the color-balancingcomponent, such that when viewed by an external observer, the ophthalmicsystem as a whole has a cosmetically acceptable appearance. For example,the ophthalmic system as a whole may look clear or mostly clear.

FIG. 1A shows an ophthalmic system including a posterior blue blockingcomponent 101 and an anterior color-balancing component 102. Eachcomponent has a concave posterior side or surface 110, 115 and a convexanterior side or surface 120, 125. In system 100, the posterior blueblocking component 101 may be or include an ophthalmic component, suchas a single vision lens, wafer or optical pre-form. The single visionlens, wafer or optical pre-form may be tinted or dyed to perform blueblocking. The anterior color-balancing component 102 may comprise asurface cast layer, applied to the single vision lens, wafer or opticalpre-form according to known techniques. For example, the surface castlayer may be affixed or bonded to the single vision lens, wafer oroptical pre-form using visible or UV light, or a combination of the two.

The surface cast layer may be formed on the convex side of the singlevision lens, wafer or optical pre-form. Since the single vision lens,wafer or optical pre-form has been tinted or dyed to perform blueblocking, it may have a yellow or amber color that is undesirablecosmetically. Accordingly, the surface cast layer may, for example, betinted with a suitable proportion of blue tinting/dye, or a suitablecombination of red and green tinting/dyes.

The surface cast layer may be treated with color balancing additivesafter it is applied to the single vision lens, wafer or optical pre-formthat has already been processed to make it blue blocking. For example,the blue blocking single vision lens, wafer or optical pre-form with thesurface cast layer on its convex surface may be immersed in a heatedtint pot which has the appropriate proportions and concentrations ofcolor balancing dyes in a solution. The surface cast layer will take upthe color balancing dyes from the solution. To prevent the blue blockingsingle vision lens, wafer or optical pre-form from absorbing any of thecolor balancing dyes, its concave surface may be masked or sealed offwith a dye resist, e.g. tape or wax or other coating. This isillustrated in FIG. 2, which shows an ophthalmic system 100 with a dyeresist 201 on the concave surface of the single vision lens, wafer oroptical pre-form 101. The edges of the single vision lens, wafer oroptical pre-form may be left uncoated to allow them to becomecosmetically color adjusted. This may be important for negative focallenses having thick edges.

FIG. 1B shows another ophthalmic system 150 in which the anteriorcolor-balancing component 104 may be or include an ophthalmic component,such as a single vision or multi-focal lens, wafer or optical pre-form.The posterior blue blocking component 103 may be a surface cast layer.To make this combination, the convex surface of the color balancingsingle vision lens, wafer or optical pre-form may be masked with a dyeresist as described above, to prevent it taking up blue blocking dyeswhen the combination is immersed in a heated tint pot containing a blueblocking dye solution. Meanwhile, the exposed surface cast layer willtake up the blue blocking dyes.

It should be understood that the surface cast layer could be used incombination with a multi-focal, rather than a single vision, lens, waferor optical pre-form. In addition, the surface cast layer could be usedto add power to a single vision lens, wafer or optical pre-form,including multi-focal power, thus converting the single vision lens,wafer or optical pre-form to a multi-focal lens, with either a lined orprogressive type addition. Of course, the surface cast layer could alsobe designed to add little or no power to the single vision lens, waferor optical pre-form.

FIG. 3 shows blue blocking and color balancing functionality integratedinto an ophthalmic component. More specifically, in ophthalmic lens 300,a portion 303 corresponding to a depth of tint penetration into anotherwise clear or mostly clear ophthalmic component 301 at a posteriorregion thereof may be blue blocking. Further, a portion 302,corresponding to a depth of tint penetration into the otherwise clear ormostly clear ophthalmic component 301 at a frontal or anterior regionthereof may be color balancing. The system illustrated in FIG. 3 may beproduced as follows. The ophthalmic component 301 may, for example,initially be a clear or mostly clear single vision or multi-focal lens,wafer or optical pre-form. The clear or mostly clear single vision ormulti-focal lens, wafer or optical pre-form may be tinted with a blueblocking tint while its front convex surface is rendered non-absorptive,e.g., by masking or coating with a dye resist as described previously.As a result, a portion 303, beginning at the posterior concave surfaceof the clear or mostly clear single vision or multi-focal lens, wafer oroptical pre-form 301 and extending inwardly, and having blue blockingfunctionality, may be created by tint penetration. Then, theanti-absorbing coating of the front convex surface may be removed. Ananti-absorbing coating may then be applied to the concave surface, andthe front convex surface and peripheral edges of the single vision ormulti-focal lens, wafer or optical pre-form may be tinted (e.g. byimmersion in a heated tint pot) for color balancing. The color balancingdyes will be absorbed by the peripheral edges and a portion 302beginning at the front convex surface and extending inwardly, that wasleft untinted due to the earlier coating. The order of the foregoingprocess could be reversed, i.e., the concave surface could first bemasked while the remaining portion was tinted for color balancing. Then,the coating could be removed and a depth or thickness at the concaveregion left untinted by the masking could be tinted for blue blocking.

Referring now to FIG. 4, an ophthalmic system 400 may be formed using anin-mold coating. More specifically, an ophthalmic component 401 such asa single vision or multi-focal lens, wafer or optical pre-form which hasbeen dyed/tinted with a suitable blue blocking tint, dye or otheradditive may be color balanced via surface casting using a tintedin-mold coating 403. The in-mold coating 403, comprising a suitablelevel and/or mixtures of color balancing dyes, may be applied to theconvex surface mold (i.e., a mold, not shown, for applying the coating403 to the convex surface of the ophthalmic component 401). A colorlessmonomer 402 may be filled in and cured between the coating 403 andophthalmic component 401. The process of curing the monomer 402 willcause the color balancing in-mold coating to transfer itself to theconvex surface of the ophthalmic component 401. The result is a blueblocking ophthalmic system with a color balancing surface coating. Thein-mold coating could be, for example, an anti-reflective coating or aconventional hard coating.

Referring now to FIG. 5, an ophthalmic system 500 may comprise twoophthalmic components, one blue blocking and the other color balancing.For example, a first ophthalmic component 501 could be a back singlevision or concave surface multi-focal lens, wafer or optical pre-form,dyed/tinted with the appropriate blue blocking tint to achieve thedesired level of blue blocking. A second ophthalmic component 503 couldbe a front single vision or convex surface multi-focal lens, wafer oroptical pre-form, bonded or affixed to the back single vision or concavesurface multi-focal lens, wafer or optical pre-form, for example using aUV or visible curable adhesive 502. The front single vision or convexsurface multi-focal lens, wafer or optical pre-form could be renderedcolor balancing either before or after it was bonded with the backsingle vision or concave surface multi-focal lens, wafer or opticalpre-form. If after, the front single vision or convex surfacemulti-focal lens, wafer or optical pre-form could be rendered colorbalancing, for example, by techniques described above. For example, theback single vision or concave surface multi-focal lens, wafer or opticalpre-form may be masked or coated with a dye resist to prevent it takingup color balancing dyes. Then, the bonded back and front portions may betogether placed in a heated tint pot containing a suitable solution ofcolor balancing dyes, allowing the front portion to take up colorbalancing dyes.

Any of the above-described embodiments systems, may be combined with oneor more anti-reflective (AR) components. This is shown in FIG. 6, by wayof example, for the ophthalmic lenses 100 and 150 shown in FIGS. 1A and1B. In FIG. 6, a first AR component 601, e.g. a coating, is applied tothe concave surface of posterior blue blocking element 101, and a secondAR component 602 is applied to the convex surface of color balancingcomponent 102. Similarly, a first AR component 601 is applied to theconcave surface of posterior blue blocking component 103, and a secondAR component 602 is applied to the convex surface of color balancingcomponent 104.

FIGS. 7A-7C show further exemplary systems including a blue blockingcomponent and a color-balancing component. In FIG. 7A, an ophthalmicsystem 700 includes a blue blocking component 703 and a color balancingcomponent 704 that are formed as adjacent, but distinct, coatings orlayers on or adjacent to the anterior surface of a clear or mostly clearophthalmic lens 702. The blue blocking component 703 is posterior to thecolor-balancing component 704. On or adjacent to the posterior surfaceof the clear or mostly clear ophthalmic lens, an AR coating or otherlayer 701 may be formed. Another AR coating or layer 705 may be formedon or adjacent to the anterior surface of the color-balancing layer 704.

In FIG. 7B, the blue blocking component 703 and color-balancingcomponent 704 are arranged on or adjacent to the posterior surface ofthe clear or mostly clear ophthalmic lens 702. Again, the blue blockingcomponent 703 is posterior to the color-balancing component 704. An ARcomponent 701 may be formed on or adjacent to the posterior surface ofthe blue blocking component 703. Another AR component 705 may be formedon or adjacent to the anterior surface of the clear or mostly clearophthalmic lens 702.

In FIG. 7C, the blue blocking component 703 and the color-balancingcomponent 704 are arranged on or adjacent to the posterior and theanterior surfaces, respectively, of the clear ophthalmic lens 702.Again, the blue blocking component 703 is posterior to thecolor-balancing component 704. An AR component 701 may be formed on oradjacent to the posterior surface of the blue blocking component 703,and another AR component 705 may be formed on or adjacent to theanterior surface of the color-balancing component 704.

FIGS. 8A and 8B show an ophthalmic system 800 in which functionality toboth block blue light wavelengths and to perform color balancing may becombined in a single component 803. For example, the combinedfunctionality component may block blue light wavelengths and reflectsome green and red wavelengths as well, thus neutralizing the blue andeliminating the appearance of a dominant color in the lens. The combinedfunctionality component 803 may be arranged on or adjacent to either theanterior or the posterior surface of a clear ophthalmic lens 802. Theophthalmic lens 800 may further include an AR component 801 on oradjacent to either the anterior or the posterior surface of the clearophthalmic lens 802.

To quantify the effectiveness of a color balancing component, it may beuseful to observe light reflected and/or transmitted by a substrate ofan ophthalmic material. The observed light may be characterized by itsCIE coordinates to indicate the color of observed light; by comparingthese coordinates to the CIE coordinates of the incident light, it ispossible to determine how much the color of the light was shifted due tothe reflection/transmission. White light is defined to have CIEcoordinates of (0.33, 0.33). Thus, the closer an observed light's CIEcoordinates are to (0.33, 0.33), the “more white” it will appear to anobserver. To characterize the color shifting or balancing performed by alens, (0.33, 0.33) white light may be directed at the lens, and the CIEof reflected and transmitted light observed. If the transmitted lighthas a CIE of about (0.33, 0.33), there will be no color shifting, anditems viewed through the lens will have a natural appearance, i.e., thecolor will not be shifted relative to items observed without the lens.Similarly, if the reflected light has a CIE of about (0.33, 0.33), thelens will have a natural cosmetic appearance, i.e., it will not appeartinted to an observer viewing a user of the lens or ophthalmic system.Thus, it is desirable for transmitted and reflected light to have a CIEas close to (0.33, 0.33) as possible.

FIG. 9 shows a CIE plot indicating the observed colors corresponding tovarious CIE coordinates. A reference point 900 indicates the coordinates(0.33, 0.33). Although the central region of the plot typically isdesignated as “white,” some light having CIE coordinates in this regioncan appear slightly tinted to a viewer. For example, light having CIEcoordinates of (0.4, 0.4) will appear yellow to an observer. Thus, toachieve a color-neutral appearance in an ophthalmic system, it isdesirable for (0.33, 0.33) light (i.e., white light) that is transmittedand/or reflected by the system to have CIE coordinates as close to(0.33, 0.33) as possible after the transmission/reflection. The CIE plotshown in FIG. 9 will be used herein as a reference to show the colorshifts observed with various systems, though the labeled regions will beomitted for clarity.

Absorbing dyes may be included in the substrate material of anophthalmic lens by injection molding the dye into the substrate materialto produce lenses with specific light transmission and absorptionproperties. These dye materials can absorb at the fundamental peakwavelength of the dye or at shorter resonance wavelengths due to thepresence of a Soret band typically found in porphyrin materials.Exemplary ophthalmic materials include various glasses and polymers suchas CR-39®, TRIVEX®, polycarbonate, polymethylmethacrylate, silicone, andfluoropolymers, though other materials may be used and are known forvarious ophthalmic systems.

By way of example only, Gentex day material E465 transmittance andabsorbance is shown in FIGS. 10-11. The Absorbance (A) is related to thetransmittance (T) by the equation, A=log₁₀(1/T). In this case, thetransmittance is between 0 and 1 (0<T<1). Often transmittance is expressas a percentage, i.e., 0%<T<100%. The E465 dye blocks those wavelengthsless than 465 and is normally provided to block these wavelengths withhigh optical density (OD>4). Similar products are available to blockother wavelengths. For example, E420 from Gentex blocks wavelengthsbelow 420 nm. Other exemplary dyes include porphyrins, perylene, andsimilar dyes that can absorb at blue wavelengths.

The absorbance at shorter wavelengths can be reduced by a reduction ofthe dye concentration. This and other dye materials can achieve atransmittance of ˜50% in the 430 nm region. FIG. 12 shows thetransmittance of a polycarbonate substrate with a dye concentrationsuitable for absorbing in the 430 nm range, and with some absorption inthe range of 420 nm-440 nm. This was achieved by reducing theconcentration of the dye and including the effects of a polycarbonatesubstrate. The rear surface is at this point not antireflection coated.

The concentration of dye also may affect the appearance and color shiftof an ophthalmic system. By reducing the concentration, systems withvarying degrees of color shift may be obtained. A “color shift” as usedherein refers to the amount by which the CIE coordinates of a referencelight change after transmission and/or reflection of the ophthalmicsystem. It also may be useful to characterize a system by the colorshift causes by the system due to the differences in various types oflight typically perceived as white (e.g., sunlight, incandescent light,and fluorescent light). It therefore may be useful to characterize asystem based on the amount by which the CIE coordinates of incidentlight are shifted when the light is transmitted and/or reflected by thesystem. For example, a system in which light with CIE coordinates of(0.33, 0.33) becomes light with a CIE of (0.30, 0.30) after transmissionmay be described as causing a color shift of (−0.03, −0.03), or, moregenerally, (±0.03, ±0.03). Thus the color shift caused by a systemindicates how “natural” light and viewed items appear to a wearer of thesystem. As further described below, systems causing color shifts of lessthan (±0.05, ±0.05) to (±0.02, ±0.02) have been achieved.

A reduction in short-wavelength transmission in an ophthalmic system maybe useful in reducing cell death due to photoelectric effects in theeye, such as excitation of A2E. It has been shown that reducing incidentlight at 430±30 nm by about 50% can reduce cell death by about 80%. See,for example, Janet R. Sparrow et al., “Blue light-absorbing intraocularlens and retinal pigment epithelium protection in vitro,” J. CataractRefract. Surg. 2004, vol. 30, pp. 873-78, the disclosure of which isincorporated by reference in its entirety. It is further believed thatreducing the amount of blue light, such as light in the 430-460 nmrange, by as little as 5% may similarly reduce cell death and/ordegeneration, and therefore prevent or reduce the adverse effects ofconditions such as atrophic age-related macular degeneration.

Although an absorbing dye may be used to block undesirable wavelengthsof light, the dye may produce a color tint in the lens as a side effect.For example, many blue-blocking ophthalmic lenses have a yellow coloringthat is often undesirable and/or aesthetically displeasing. To offsetthis coloring, a color balancing coating may be applied to one or bothsurfaces of a substrate including the absorbing dye therein.

Antireflection (AR) coatings (which are interference filters) arewell-established within the commercial ophthalmic coating industry. Thecoatings typically are a few layers, often less than 10, and typicallyare used to reduce the reflection from the polycarbonate surface to lessthan 1%. An example of such a coating on a polycarbonate surface isshown in FIG. 13. The color plot of this coating is shown in FIG. 14 andit is observed that the color is quite neutral. The total reflectancewas observed to be 0.21%. The reflected light was observed to have CIEcoordinates of (0.234, 0.075); the transmitted light had CIE coordinatesof (0.334, 0.336).

AR coatings may be applied to both surfaces of a lens or otherophthalmic device to achieve a higher transmittance. Such aconfiguration is shown in FIG. 15 where the darker line 1510 is the ARcoated polycarbonate and the thinner line 1520 is an uncoatedpolycarbonate substrate. This AR coating provides a 10% increase intotal transmitted light. There is some natural loss of light due toabsorption in the polycarbonate substrate. The particular polycarbonatesubstrate used for this example has a transmittance loss ofapproximately 3%. In the ophthalmic industry AR coatings generally areapplied to both surfaces to increase the transmittance of the lens.

In systems according to the present invention, AR coatings or othercolor balancing films may be combined with an absorbing dye to allow forsimultaneous absorption of blue wavelength light, typically in the 430nm region, and increased transmittance. As previously described,elimination of the light in the 430 nm region alone typically results ina lens that has some residual color cast. To spectrally tailor the lightto achieve a color neutral transmittance, at least one of the ARcoatings may be modified to adjust the overall transmitted color of thelight. In ophthalmic systems according to the invention, this adjustmentmay be performed on the front surface of the lens to create thefollowing lens structure:

Air (farthest from the user's eye)/Front convex lens coating/Absorbingophthalmic lens substrate/rear concave anti-reflection coating/Air(closest to the user's eye).

In such a configuration, the front coating may provide spectraltailoring to offset the color cast resulting from the absorption in thesubstrate in addition to the antireflective function typically performedin conventional lenses. The lens therefore may provide an appropriatecolor balance for both transmitted and reflected light. In the case oftransmitted light the color balance allows for proper color vision; inthe case reflected light the color balance may provide the appropriatelens aesthetics.

In some cases, a color balancing film may be disposed between two layersof other ophthalmic material. For example, a filter, AR film, or otherfilm may be disposed within an ophthalmic material. For example, thefollowing configuration may be used:

Air (farthest from the user's eye)/ophthalmic material/film/ophthalmicmaterial/air (closest to user's eye).

The color balancing film also may be a coating, such as a hardcoat,applied to the outer and/or inner surface of a lens. Otherconfigurations are possible. For example, referring to FIG. 3, anophthalmic system may include an ophthalmic material 301 doped with ablue-absorbing dye and one or more color balancing layers 302, 303. Inanother configuration, an inner layer 301 may be a color balancing layersurrounded by ophthalmic material 302, 303 doped with a blue-absorbingdye. Additional layers and/or coatings, such as AR coatings, may bedisposed on one or more surfaces of the system. It will be understoodhow similar materials and configurations may be used, for example in thesystems described with respect to FIGS. 4-8B.

Thus, optical films and/or coatings such as AR coatings may be used tofine-tune the overall spectral response of a lens having an absorbingdye. Transmission variation across the visible spectrum is well knownand varies as a function of the thickness and number of layers in theoptical coating. In the invention one or more layers can be used toprovide the needed adjustment of the spectral properties.

In an exemplary system, color variation is produced by a single layer ofTiO₂ (a common AR coating material). FIG. 16 shows the spectraltransmittance of a 106 nm thick single layer of TiO₂. The color plot ofthis same layer is shown in FIG. 17. The CIE color coordinates (x, y)1710 shown for the transmitted light are (0.331, 0.345). The reflectedlight had CIE coordinates of (0.353, 0.251) 1720, resulting in apurplish-pink color.

Changing the thickness of the TiO₂ layer changes the color of thetransmitted light as shown in the transmitted spectra and color plot fora 134 nm layer, shown in FIGS. 18 and 19 respectively. In this system,the transmitted light exhibited CIE coordinates of (0.362, 0.368) 1910,and the reflected light had CIE coordinates of (0.209, 0.229) 1920. Thetransmission properties of various AR coatings and the prediction orestimation thereof are known in the art. For example, the transmissioneffects of an AR coating formed of a known thickness of an AR materialmay be calculated and predicted using various computer programs.Exemplary, non-limiting programs include Essential Macleod Thin FilmsSoftware available from Thin Film Center, Inc., TFCalc available fromSoftware Spectra, Inc., and FilmStar Optical Thin Film Softwareavailable from FTG Software Associates. Other methods may be used topredict the behavior of an AR coating or other similar coating or film.

In systems according to the present invention, a blue-absorbing dye maybe combined with a coating or other film to provide a blue blocking,color balanced system. The coating may be an AR coating on the frontsurface that is modified to correct the color of the transmitted and/orreflected light. The transmittance and color plot of an exemplary ARcoating are shown in FIGS. 20 and 21, respectively. FIGS. 22 and 23 showthe transmittance and color plot, respectively, for a polycarbonatesubstrate having a blue absorbing dye without an AR coating. The dyedsubstrate absorbs most strongly in the 430 nm region, including someabsorption in the 420-440 nm region. The dyed substrate may be combinedwith an appropriate AR coating as illustrated in FIGS. 20-21 to increasethe overall transmittance of the system. The transmittance and colorplot for a dyed substrate having a rear AR coating are shown in FIGS. 24and 25, respectively.

An AR coating also may be applied to the front of an ophthalmic system(i.e., the surface farthest from the eye of a wearer of the system),resulting in the transmittance and color plot shown in FIGS. 26 and 27,respectively. Although the system exhibits a high transmission andtransmitted light is relatively neutral, the reflected light has a CIEof (0.249, 0.090). Therefore, to more completely color balance theeffects of the blue absorbing dye, the front AR coating may be modifiedto achieve the necessary color balance to produce a color neutralconfiguration. The transmittance and the color plot of thisconfiguration are shown in FIGS. 28 and 29 respectively. In thisconfiguration, both the transmitted and reflected light may be optimizedto achieve color neutrality. It may be preferred for the interiorreflected light to be about 6%. Should the reflectivity level beannoying to the wearer of the system, the reflection can be furtherreduced by way of adding an additional different absorbing dye into thelens substrate that would absorb a different wavelength of visiblelight. However, the design of this configuration achieves remarkableperformance and satisfies the need for a blue blocking, color balancedophthalmic system as described herein. The total transmittance is over90% and both the transmitted and reflected colors are quite close to thecolor neutral white point. As shown in FIG. 27, the reflected light hasa CIE of (0.334, 0.334), and the transmitted light has a CIE of (0.341,0.345), indicating little or no color shifting.

In some configurations, the front modified anti-reflection coating canbe designed to block 100% of the blue light wave length to be inhibited.However, this may result in a back reflection of about 9% to 10% for thewearer. This level of reflectivity can be annoying to the wearer. Thusby combining an absorbing dye into the lens substrate this reflectionwith the front modified anti-reflection coating the desired effect canbe achieved along with a reduction of the reflectivity to a level thatis well accepted by the wearer. The reflected light observed by a wearerof a system including one or more AR coatings may be reduced to 8% orless, or more preferably 3% or less.

The combination of a front and rear AR coating may be referred to as adielectric stack, and various materials and thicknesses may be used tofurther alter the transmissive and reflective characteristics of anophthalmic system. For example, the front AR coating and/or the rear ARcoating may be made of different thicknesses and/or materials to achievea particular color balancing effect. In some cases, the materials usedto create the dielectric stack may not be materials traditionally usedto create antireflective coatings. That is, the color balancing coatingsmay correct the color shift caused by a blue absorbing dye in thesubstrate without performing an antireflective function.

As discussed previously, filters are another technique for blueblocking. Accordingly, any of the blue blocking components discussedcould be or include or be combined with blue blocking filters. Suchfilters may include rugate filters, interference filters, band-passfilters, band-block filters, notch filters or dichroic filters.

In embodiments of the invention, one or more of the above-disclosedblue-blocking techniques may be used in conjunction with otherblue-blocking techniques. By way of example only, a lens or lenscomponent may utilize both a dye/tint and a rugate notch filter toeffectively block blue light.

Any of the above-disclosed structures and techniques may be employed inan ophthalmic system according to the present invention to performblocking of blue light wavelengths at or near 400-460 nm. For example,in embodiments the wavelengths of blue light blocked may be within apredetermined range. In embodiments, the range may be 430 nm±30 nm. Inother embodiments, the range may be 430 nm±20 nm. In still otherembodiments, the range may be 430 nm±10 nm. In embodiments, theophthalmic system may limit transmission of blue wavelengths within theabove-defined ranges to substantially 90% of incident wavelengths. Inother embodiments, the ophthalmic system may limit transmission of theblue wavelengths within the above-defined ranges to substantially 80% ofincident wavelengths. In other embodiments, the ophthalmic system maylimit transmission of the blue wavelengths within the above-definedranges to substantially 70% of incident wavelengths. In otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 60% ofincident wavelengths. In other embodiments, the ophthalmic system maylimit transmission of the blue wavelengths within the above-definedranges to substantially 50% of incident wavelengths. In otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 40% ofincident wavelengths. In still other embodiments, the ophthalmic systemmay limit transmission of the blue wavelengths within the above-definedranges to substantially 30% of incident wavelengths. In still otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 20% ofincident wavelengths. In still other embodiments, the ophthalmic systemmay limit transmission of the blue wavelengths within the above-definedranges to substantially 10% of incident wavelengths. In still otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 5% ofincident wavelengths. In still other embodiments, the ophthalmic systemmay limit transmission of the blue wavelengths within the above-definedranges to substantially 1% of incident wavelengths. In still otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 0% ofincident wavelengths. Stated otherwise, attenuation by the ophthalmicsystem of the electromagnetic spectrum at wavelengths in theabove-specified ranges may be at least 10%; or at least 20%; or at least30%; or at least 40%; or at least 50%; or at least 60%; or at least 70%;or at least 80%; or at least 90%; or at least 95%; or at least 99%; orsubstantially 100%.

In some cases it may be particularly desirable to filter a relativelysmall portion of the blue spectrum, such as the 400 nm-460 nm region.For example, it has been found that blocking too much of the bluespectrum can interfere with scotopic vision and circadian rhythms.Conventional blue blocking ophthalmic lenses typically block a muchlarger amount of a wide range of the blue spectrum, which can adverselyaffect the wearer's “biological clock” and have other adverse effects.Thus, it may be desirable to block a relatively narrow range of the bluespectrum as described herein. Exemplary systems that may filter arelatively small amount of light in a relatively small range includesystem that block or absorb 5-50%, 5-20%, and 5-10% of light having awavelength of 400 nm-460 nm, 410 nm-450 nm, and 420 nm-440 nm.

At the same time as wavelengths of blue light are selectively blocked asdescribed above, at least 80%, or at least 85%, and in other embodimentsat least 90-95%, of other portions of the visual electromagneticspectrum may be transmitted by the ophthalmic system. Stated otherwise,attenuation by the ophthalmic system of the electromagnetic spectrum atwavelengths outside the blue light spectrum, e.g. wavelengths other thanthose in a range around 430 nm may be 20% or less, 15% or less, 10% orless, and in other embodiments, 5% or less.

Additionally, embodiments of the present invention may further blockultra-violet radiation the UVA and UVB spectral bands as well asinfra-red radiation with wavelengths greater than 700 nm.

Any of the above-disclosed ophthalmic system may be incorporated into anarticle of eyewear, including externally-worn eyewear such aseyeglasses, sunglasses, goggles or contact lenses. In such eyewear,because the blue-blocking component of the systems is posterior to thecolor balancing component, the blue-blocking component will always becloser to the eye than the color-balancing component when the eyewear isworn. The ophthalmic system may also be used in such articles ofmanufacture as surgically implantable intra-ocular lenses.

Several embodiments of the invention are specifically illustrated and/ordescribed herein. However, it will be appreciated that modifications andvariations of the invention are covered by the above teachings andwithin the purview of the appended claims without departing from thespirit and intended scope of the invention.

1. An ophthalmic system comprising: a first layer comprising: anophthalmic material; and a dye that absorbs at least 5% of light in awavelength range; and a film disposed on the first layer; wherein thefilm corrects a color imbalance resulting from absorption of light bythe dye; and wherein the system has an average transmission of at least80% across the visible spectrum.
 2. The system of claim 1, furthercomprising a second layer of the ophthalmic material disposed on thefilm, wherein the film is disposed between the first layer and thesecond layer.
 3. The system of claim 1 wherein the wavelength range is400 nm-460 nm.
 4. The system of claim 1 wherein the wavelength range is420 nm-440 nm.
 5. The system of claim 1 wherein the dye absorbs 5%-50%of light having a wavelength of 400 nm-460 nm.
 6. The system of claim 1wherein the dye absorbs 5%-20% of light having a wavelength of 400nm-460 nm.
 7. The system of claim 1 wherein white light has a CIE of(0.33±0.05, 0.33±0.05) when transmitted through the lens.
 8. The systemof claim 1 wherein white light has a CIE of (0.33±0.02, 0.33±0.02) whentransmitted through the lens.
 9. The system of claim 1 wherein the firstlayer is an antireflective coating disposed on the outer surface of theophthalmic substrate.
 10. The system of claim 1 further comprising anantireflective coating disposed on a surface of the system closest tothe eye of a wearer of the system.
 11. The system of claim 10 whereinthe reflected light observed by a wearer of the system is less than 8%.12. The system of claim 10 wherein the reflected light observed by awearer of the system is less than 3%.
 13. The system of claim 1 whereinthe dye is perylene.
 14. The system of claim 1 wherein the dye is aporphyrin.
 15. An ophthalmic system that absorbs at least 5% of lighthaving a wavelength of 400 nm-460 nm, wherein the system has an averagetransmission of at least 80% across the visible spectrum and causes acolor shift of not more than (±0.05, ±0.05) for light transmittedthrough the system.
 16. The system of claim 15 wherein the system has anaverage transmission of at least 90% across the visible spectrum. 17.The system of claim 15 wherein the system absorbs 5%-50% of light havinga wavelength of 400 nm-460 nm.
 18. The system of claim 15 wherein thesystem causes a color shift of not more than (±0.02, ±0.02).
 19. Amethod of making an ophthalmic device, comprising: doping an ophthalmicmaterial with a dye that absorbs at least 5% of light having awavelength of 400 nm-460 nm; molding the ophthalmic material into afirst layer; and depositing a film on the first layer; wherein the filmcorrects a color imbalance resulting from absorption of light by thedye.
 20. The method of claim 19 wherein the wavelength range is 420nm-440 nm.
 21. The method of claim 19 wherein the dye absorbs 5%-50% oflight having a wavelength of 400 nm-460 nm.
 22. The method of claim 19wherein the dye absorbs 5%-20% of light having a wavelength of 400nm-460 nm.
 23. The method of claim 19 wherein white light has a CIE of(0.33±0.05, 0.33±0.05) when transmitted through the device.
 24. Themethod of claim 19 wherein white light has a CIE of (0.33±0.02,0.33±0.02) when transmitted through the device.
 25. The method of claim19 wherein the film is an antireflective coating.
 26. The method ofclaim 19, further comprising: depositing a second layer of theophthalmic material on the film, wherein the film is disposed betweenthe first layer and the second layer.